The present invention relates to a shield for fiber optic connectors and cables which minimizes the electromagnetic interference (EMI) energy entering or leaving an enclosure for associated electrical computer components.
As digital data and edge rates increase, multi-processing computer systems increasingly use fiber optic links for data transmission. Particularly, systems for transmitting large blocks of data in short intervals of time and systems for transmitting high speed data over relatively long distances use fiber optic links. A common high speed application is the connection between computer nodes in parallel processing computing and the high data rate connections between computers and data storage.
A common misperception associated with the use of fiber optic links is that fiber optic links eliminate all problems with electromagnetic interference (EMI) regulatory certification compliance. This misperception (that use of fiber optics eliminates EMI concerns) likely stems from past fiber optic systems when either analog signals or low speed digital signals were transmitted by the fiber optics. Probably due to this misperception, most fiber optic connectors are not designed to minimize EMI effects.
Currently, modern high data rate fiber optic data transmission systems present a range of significant EMI problems. While the fiber optic cable does not radiate electromagnetic energy, the electrical computer components that feed the optical transmission system can cause EMI to radiate. Additionally, EMI problems may arise due to susceptibility of the electronic system to electromagnetic noise created by neighboring equipment that can create component damage, system upset, data error or related problems.
EMI may enter a computer system in various ways such as via various apertures and conducted points of entry associated with a typical electrical enclosure. Particularly, EMI may enter a computer system enclosure via the substantial electrical aperture associated with a fiber optic cable connector. This electrical aperture occurs between the fiber optic connector and the electrical enclosure because the fiber optic connector body is constructed from plastic, rather than metal (or any other electrically conductive material). This electrical aperture is a common point of entry or exit for EMI energy in current systems with fiber optic links.
Accordingly, there is a need for a shield for fiber optic connectors and cables which minimizes the EMI energy entering or leaving an enclosure via the fiber optic connector electrical aperture.
In accordance with the teachings of the present invention, a shield for fiber optic connectors and cables is provided. This shield minimizes the effects of EMI either radiating from or radiating into an electronic enclosure. Embodiments include this shield as an integral part of the enclosure chassis, a separate shield, or integrated into the fiber optic cable and connector.